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Cobalt germanides have been widely studied as semiconductor contact materials, but recent theoretical studies suggest that they may also be excellent catalysts for methane steam reforming with stabilities and activities comparable to more expensive noble metal catalysts. We have sputter deposited CoGe alloy films and characterized their structure and morphology after post-deposition annealing in high vacuum up to 1000 °C. We used X-ray photoelectron spectroscopy to study the initial oxidation of amorphous and crystalline CoGe alloy surfaces under low pressures of O2 and H2O. The oxidation rate in O2 was found to be faster for an amorphous CoGe surface compared to a crystalline surface. We also found that there was little difference in the oxidation rate in H2O for either amorphous or crystalline surfaces. During O2 oxidation, the crystalline surface preferentially forms GeO and the amorphous surface preferentially forms GeO2. We have also observed preferential oxidation of Ge in the CoGe thin films. During temperature programmed desorption studies, we found that GeO desorption begins near 350 °C and that GeO2 decomposes to GeO and desorbs near 700 °C. More studies of CoGe catalysts are warranted, however GeO desorption may be a concern under reaction conditions when the film is subjected to an oxidizing environment.

Aneuploidy is frequently associated with disease and developmental abnormalities. It is also a key characteristic of cancer. Several model systems have been developed to study the role of chromosomal instability and aneuploidy in tumorigenesis. The results are surprisingly complex, with the conditions sometimes promoting and sometimes inhibiting tumour formation. Here, we review the effects of aneuploidy and chromosomal instability in cells and model systems of cancer, propose a model that could explain these complex findings and discuss how the aneuploid condition could be exploited in cancer therapy.

Aneuploidy decreases cellular fitness, yet it is also associated with cancer, a disease of enhanced proliferative capacity. To investigate one mechanism by which aneuploidy could contribute to tumorigenesis, we examined the effects of aneuploidy on genomic stability. We analyzed 13 budding yeast strains that carry extra copies of single chromosomes and found that all aneuploid strains exhibited one or more forms of genomic instability. Most strains displayed increased chromosome loss and mitotic recombination, as well as defective DNA damage repair. Aneuploid fission yeast strains also exhibited defects in mitotic recombination. Aneuploidy-induced genomic instability could facilitate the development of genetic alterations that drive malignant growth in cancer.

Introduction. True aneurysms of the extracranial internal carotid artery are rare lesions. Surgical treatment is considered to be the best therapeutic option. However, the use of the intraluminal shunt remains controversial. Case report. We reported a case of a giant extracranial internal carotid artery aneurysm treated by reconstructive surgery. A 76-year-old woman was referred with a pulsatile mass inside her mouth, associated with dizziness and dysarthria. There was no history of cerebrovascular symptoms, neck pain, or cervical trauma. A magnetic resonance scan showed a 45 mm aneurysm of the internal carotid artery (ICA), and kinking of ICA. Angiography demonstrated a saccular ICA aneurysm, with a lengthening and tortuosity of the ICA. The aneurysm and the carotid artery branches were easily exposed through a standard anterior cervical incision. After resection of the aneurysm, a Javid shunt was inserted between the common and internal carotid arteries, and end-to-end repair of ICA was easily performed due to ICA redundancy. The aneurysm was of atherosclerotic origin. Four months after the operation, the patient showed a complete recovery from peripheral neurological deficit. Discussion. Our results show that surgical reconstruction is a satisfactory therapeutic choice in the management of extracranial carotid artery aneurysms in order to avoid rupture, thromboembolism and cerebrovascular insufficiency. To date, there has been little experience with endoluminal exclusion techniques and the long-term effectiveness is still uncertain. .

Natural or deliberate activation of the immune system of pathogen-free mice markedly affected their response to an autoimmune-inducing stimulus. Specifically, mice immunized with rat red blood cells were found to make antibodies reactive with both rat and mouse erythrocytes. Animals housed for an extended period in a conventional environment developed an autoimmune response twice as fast as those kept in isolators. In an attempt to emulate this effect, mice kept in a sterile environment were infected with a potent polyclonal activator of B lymphocytes, lactate dehydrogenase-elevating virus, at the same time as they were inoculated with rat erythrocytes. Whereas uninfected animals developed a progressively increasing autoantibody titer, infected mice quickly attained high anti-erythrocyte autoantibody titers that remained rather constant. Contrary to circulating autoantibodies, bound anti-erythrocyte antibodies decreased with time. Virus infection enhanced all the IgG subclass responses, with the exception of IgG1, to both rat and mouse erythrocytes. None of the modifications of the autoimmune responses resulted in anemia.

GaAs substrates were pre-patterned by electron beam (e-beam) lithography and wet-chemically etched holes. The hole structures, presented here, enable growth of site-controlled InAs quantum dots with low dot density in the range of 10^8cm^-^2 by molecular beam epitaxy (MBE). In order to reduce defect related non-radiative recombination processes at the etched surface, wet-chemical etching and a modified growth of stacked quantum dot layers are developed. The total buffer layer thickness could be increased to 55nm GaAs by only one overgrowth step of a quantum dot seed layer in comparison to strain-coupled multi-stacked structure with typically 10nm buffer layer thickness between each stack.

Lymphocytic Choriomeningitis (LCM) virus, substrain Docile, causes a chronic infection in adult C3HeB/FeJ mice. The virus also induces a severe anemia which, unlike the viremia, eventually resolves. Initially, there is frank bone marrow deficit, but the anemia persists well beyond a strong erythroid compensatory response. An immune-mediated basis for the hemolytic anemia was suggested by its abrogation in cyclophosphamide-treated mice, as well as an abnormal number of spherocytes in the circulation. We now show by ELISA assay, using either anti-mouse Ig or RBC membrane ghosts as catching antigen, that unusually high quantities of antibodies can be eluted from the RBCs of virus-infected mice. Furthermore, the high transient antibody concentration correlates with the severity of the anemia. With no evidence for complement playing a role in the anemia, these data indicate that erythrophagocytosis (via macrophage FcRs) may be the mechanism for RBC elimination. The possibility of molecular mimicry (antibody cross-reactivity between LCM and RBC membrane epitopes) was considered but appeared unlikely since the RBC antibody eluates gave no signal in an LCM-specific ELISA (which showed an ever increasing serum titer of virus-specific antibody). Isotype determination of the RBC eluates revealed the following: IgG2a much greater than IgG1 greater than IgG2b greater than IgG3 greater than IgM. The precise role, if any, of LCM-virus induced polyclonal activation (most strikingly in the IgG2a subclass) has yet to be determined.

We present site-controlled low density InAs quantum dots grown by molecular beam epitaxy with a template based overgrowth technique allowing enlarged buffer layers upto 55 nm. Growing a seeding layer of InAs quantum dots in etched holes reduces closing of the holes, so that a second layer of InAs quantum dots can be aligned to the holes after a buffer layer overgrowth. Confocal microphotoluminescence measurements show a significant decrease of the low temperature photoluminescence linewidth of the quantum dots to an average value of ∼500 μeV and a minimum width of 460 μeV. This is to be compared to 2 to 4 meV of quantum dots grown on thin buffer layers. This improvement is due to the enlarged distance to residual defects at the overgrown surface.

A photoelectrically controlled automatic dilution device and the experimental set-up for its application in maintaining cultures of micro algae permanently synchronized during repeated life cycles are described. The accuracy of dilution, synchrony, growth parameters and photosynthetic response were determined for cultures of Scenedesmus obliquus and Chlorella pyrenoidosa.

The infectivity of LCM virus suspended in solutions buffered with Tris(hydroxymethyl)aminomethane and its hydrochloride has been found to be greatly stabilized. This stabilization (studied at 4° and 37° C), however, was markedly dependent on the protein content of the solution. If the protein content became too low (by dilution and/or partial purification of the virus), the Tris effect would disappear, but could be reversed if bovine serum albumin was added before inactivation studies were begun. The sensitivity of the virus to ultrasonic irradiation also followed the pattern established above (i.e. — diluted or purified virus was inactivated to a much greater extent than virus suspended in Eagle's medium plus serum). The data also indicated that sonication could break up aggregates of virus particles.

The pathogenicity of lymphocytic choriomeningitis virus (LCMV) inoculated intracerebrally (i.c.) varies with virus strain and dose as well as with the mouse strain used as host. Recently, results have indicated that susceptibility to lethal disease correlates directly the ability of the host to produce early and high virus-specific Tc activity. However, in the present studies we demonstrate that even though this holds true in many mouse/virus combinations, it does not apply in others. Thus, in C3H mice infected with (moderately) high doses of Traub strain LCMV, early and high Tc activity was found despite a mortality rate of only 10-20%. Similarly, in C3H mice inoculated with the aggressive and docile substrains of UBC strain LCMV, which differ markedly in their pathogenicity for this mouse strain, similar kinetics of Tc induction were observed. Finally, in DBA/2 mice which do not die following infection with the otherwise lethal aggressive substrain, Tc induction could be found to be as efficient as in BALB/c mice, all of which die from acute LCM disease when infected with this virus isolate. The results indicate, therefore, that early and high Tc activity does not constitute a sufficient prerequisite for lethal disease, and that different Tc response profiles may be associated with low mortality following i.c. inoculation with LCMV.

Resistance to the acute lethal disease caused by the docile strain of lymphocytic choriomeningitis (LCM) virus varies widely between different mouse strains. In order to study the inheritance of host influence on susceptibility to this strain of LCM virus, we crossed the F1 to the parent with the recessive disease phenotype. In all cases, susceptibility was dominant. In backcross progeny obtained from matings of parental strains differing in both major histocompatibility complex (MHC) and non-MHC (SWR; C3H), 90% of the challenged mice died, indicating that at least three loci controlled susceptibility to the disease. When the parental strains carried similar MHC haplotypes but dissimilar background genes (B10.BR; CBA), 78% of the backcross mice succumbed, indicating that at least two non-MHC loci influenced disease susceptibility. It is unlikely, however, that the same two non-MHC loci are critical in all genetic combinations, since F1 produced from two H-2 identical, resistant strains (B10.BR; C3H) were found to be fully susceptible. When congenic mice, differing only in the D-end of the MHC region, were analysed, 50% of the backcross animals died, indicating that one gene in the MHC region was important; segregation analysis comparing MHC serotype and disease outcome indicated the H-2D locus itself as the determining factor.